Field of the Invention
The invention relates to a chip card including a plastic card, a semiconductor chip that is disposed in the plastic card, and contact strips which are electrically connected to the semiconductor chip and are joined to the plastic card.
One such chip card is known from European Patent 0 254 640 B1. In that known chip card, the contact strips are part of a lead frame. The semiconductor chip is disposed in the middle of the lead frame and is joined to the contact strips through the use of bonding wires. The semiconductor chip and the bonding wires are surrounded by a protective plastic composition, from which the contact strips protrude. The contact strips are joined to the plastic card in such a way that pointed securing tips of the plastic card which protrude into securing holes of the contact strips are thermally deformed so that the contact strips are retained. The plastic composition that protects the semiconductor chip fills up the entire space between the semiconductor chip and the plastic card and also acts as an additional securing device for the contact strips.
However, chip cards are also known in which the contact strips are constructed as a copper laminate on a plastic film. The contact strips are then joined to the plastic card by the plastic film.
In everyday use, chip cards are exposed to considerable bending strain and for that reason have to pass stringent tests. Therefore, even after being bent a great number of times, the chip must not be destroyed, nor may the bonding wires tear off, nor can the contact strips detach from the plastic card. In the known chip card, although the danger of detachment of the contact strips from the plastic card is slight because of the special way in which the contact strips are secured, nevertheless the danger that the contact strips will tear off under severe bending conditions is very high as a result of such securing.
In chip cards in which the contact strips are laminated on the plastic film and form a substrate module as well, the danger that large-area, rigid modules will break is very high.